Kerberos KDC TGS-REQ Request Handling NULL Pointer Dereference Remote Denial Of Service Vulnerability

do_tgs_req.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) 1.11 before 1.11.4, when a single-component realm name is used, allows remote authenticated users to cause a denial of service (daemon crash) via a TGS-REQ request that triggers an attempted cross-realm referral for a host-based service principal.